Apollo 13 Question..... (1 Viewer)

[Mark Sherman]

Hey Guys. I was watching Apollo 13 this weekend. What does GIMBLE LOCK or Close to centre Gimble mean. I take its a bad thing cause they dont want to come close to it.

 

[Jimi C]

gimbles are rings used to keep the compass level in a ship.

This is a gimble compass.


If you rotate, say, 90 degrees(down) on the x axis, and then try to rotate on the y axis, since the x axis will be aligned with the y axis, it wont rotate

 

[CharlesD]

They're referring to the pointing mechanism for the rocket motor. If you watch a Shuttle launch, one of the last things you see during the countdown is a gimbal test of the main engines, you'll see the nozzles move from side to side. Gimbal lock would be where the computer wants to point the engine in a direction beyond the available range of motion permitted by the gimbals & therefore the spacecraft would not go in the direction they want it to which would be a Bad Thing ™.

 

[Jimi C]

yea.. so i guess the idea behind that compass is the general idea behind that of the engines on the ship that was used for apollo 13?

 

[Greg_R]

It has to do when one form of rotation is mapped onto the other axis of rotation. When one axis rotates 90 degrees then it is aligned with the other axis of rotation. At this point you have 'lost' that 3rd axis and can't recover it (BAD). You can always rotate on 2 axises simultaneously to recover but this is sometimes impossible or very hard (depending on the system). Google for more info... this is a common issue with video game development (flight sims and 1st person shooters).

 

[Mark Sherman]

thanks guys